Method and apparatus for custom molding shoes and boots

ABSTRACT

A boot or shoe is formed of thermoplastic material. To better conform it to the wearer&#39;&#39;s foot, the wearer puts his foot within the boot and places it within a bag of a plastic material having a melting temperature higher than the molding temperature of the boot. A vacuum line is also placed within the bag and the top of the bag is sealed around the user&#39;&#39;s leg. Then the boot is heated to its softening temperature but below the melting point of the bag. A vacuum is then applied to the vacuum line to evacuate the air from within the bag to allow atmospheric pressure to exert a force on the bag and boot and to press it against the wearer&#39;&#39;s foot. While the vacuum is being maintained within the bag, the boot is cooled below its softening temperature so that the boot will permanently conform to the user&#39;&#39;s foot.

United States Patent 1191 Simonsen Nov. 19, 1974 METHOD AND APPARATUSFOR CUSTOM MOLDING SHOES AND BOOTS [76] Inventor: James Simonsen, 18522Pacific Coast Hwy, Malibu, Calif. 90265 22 Filed: Mar. 15,1974

211 Appl. No.: 451,352

52 us. 01. 121142 1112/ 1 g, 36/2.5 Al 511 1111.01. A431) A43d 9/00 [58]Field of Search 12/1 R, 1 F, 142 R, 142 P;

36/2.5 R, 2.5 AL

Lange et al 36/2.5 AL Dalebout 12/1 R Check et al. 12/142 P PrimaryExaminer-Patrick D. Lawson Attorney, Agent, or Firm-Miketta, Glenny,Poms & Smith Bille et a]. 12/1 F [5 7] ABSTRACT A boot or shoe is formedof thermoplastic material. To better conform it to the wearers foot, thewearer puts his foot within the boot and places it within a bag of aplastic material having a melting temperature higher than the moldingtemperature of the boot. A vacuum line is also placed within the bag andthe top of the bag is sealed around the users leg. Then the boot isheated to its softeningtemperature but below the melting point of thebag. A vacuum is then applied to the vacuum line to evacuate the airfrom within the bag to allow atmospheric pressure to exert a force onthe bag and boot and to press it against the wearers foot. While thevacuum is being maintained within the bag, the boot is cooled below itssoftening temperature so that the boot will permanently conform to theusers foot.

6 Claims, 4 Drawing Figures PATENT rm 1 9 I974 Il ull lilliall'lll! WEEMETHOD AND APPARATUS FOR CUSTOM MOLDING SHOES AND BOOTS BACKGROUND OFTHE INVENTION This invention relates generally to ski boots, shoes orother footwear wherein it is desirable to have the boot conform to theusers foot. The invention is generally related to the invention setforth in application Ser. No. 449,963, filed Mar. 1 1, 1974, to AnthonyJ. Kahmann, entitled Method of Custom Molding Footwear.

It has been recognized that it is desirable to have a boot or shoe whichconforms to the users foot when strains are being applied thereto. Footstrains occur during exercising and general athletics, but sports suchas hiking, skating, football, and mountain climbing are known to providemore severe strains to the participants foot. However, because of itsfast speed and because the foot is constantly under strains from avariety of sources, skiing provides the greatest strain to an athletesfeet.

Even in ordinary footwear, there is a need for a shoe or boot which willbetter support the foot being of such a size that the users foot willnot slide or be held too tightly at any portion of the shoe.Unfortunately, there are only a limited number of different sizes offootwear corresponding to standard lengths and standard widths, and twopeople who have the same size foot do not necessarily have similarlyshaped feet. With ordinary footwear, this difference is usually notcrucial unless there is an abnormality in the foot. However, these smallfoot differences are magnified when forces during athletics are appliedto the foot and shoe.

There have been numerous attempts to provide footwear that betterconforms to the wearers foot. In the field of ski boot manufacturing,these attempts have generally taken four directions.

The first method is to have a ski boot of soft material with adjustablebuckles so that the tightness of the shoe can be modified. This is anolder method and it is similar to that employed in ordinary footwearwherein the laces may be adjusted to make the boot or shoe morecomfortable to the user. This method has drawbacks because the laces donot cover the entire foot but merely serve to tighten the boot about theinstep. Also, the soft material, needed to assure that the boot can belaced tightly, may not provide sufficient support to the lower leg andankle necessary for efficient skiing.

The second method of improving the fit of a boot is to provide anexpandable material between the inside of the boot and the users foot.In that system, the internal portion of the boot may be fitted with abladder which can be filled with air to have the bladder apply pressureto the foot and prevent movement within the boot. Another method on thesame principle is to have a moldable foamed plastic injected within theboot when the users foot is therewithin, then allowing the material toexpand, cool, and reach its hardened temperature. These methods areimprovements over the buckle and lace methods of having the boot formedto the foot, however, these methods also have some drawbacks. The use offoam plastics requires that the user remain fairly stationary within theboot for upwards of one-half hour while the material cures. This is timeconsuming and uses up valuable time of sales personnel selling the boot.Also, the rather hot foamed plastic that is injected within the boot isuncomfortable to the user. Changes in the user's foot, for example fromgaining weight, injury, or the like cannot be compensated for becausethe foam injection alters the boot permanently. The air bladder methodhas the drawback that the air cannot completely cushion the foot fromthe violent moves in skiing. Also, the air bladder is somewhatcumbersome to fill each time the boot is to be used.

A third method of improving the fit of a boot is to provide an innerboot, inside the outer shell, which holds a jelly like material whichconforms to the wearers foot when pressure is placed against it. Thisflow material is generally placed in the inner boot at the point ofmanufacture. The drawbacks of the flow system are that the flow issubject to compression after prolonged use which results in a poorerfit, and conformation of the flow to the wearers foot causes variablethicknesses of flow material which separates the footfrom the outershell, further causing pressure points on the foot.

A fourth method has been proposed by Geller, in US. Pat. No. 3,613,271,dated Oct., 1971. The method concerns having a ski boot made fromthermoplastic material which is moldable at a temperature between and F.The boot is placed on the wearers foot and brought up to temperature.When it reaches the desired temperature, the user or other person pushesthe sides of the boot against the foot with his hands. Instead of hands,a pressure cuff could also be used. This has certain advantages over theother systems. First, a conventional thermoplastic ski boot may be usedwhich can be modified by this process. Secondly, the boot may beremolded at a later time to accommodate changes in the structure ofusers foot. Thirdly, the skier does not have to take preliminary stepssuch as inflating the bladder prior to each use.

There are certain drawbacks to this system. By having a boot moldable ata temperature between 120 and 140F, the boot could become soft in thetrunk of a car thereby changing the boots shape. The use of hands tocompress the boot about the foot causes uneven pressure application andcan result in having a boot too tight in certain places and too loose inothers. A pressure cuff does not alter this condition because itsapplication of forces is also uneven.

As taught in the aforementioned application to Kahmann, a vacuum isapplied to the inside of a boot and the resultant ambient pressureacting on the outside of the boot causes it to be drawn inwardly towardthe foot. Although the method is effective in fitting the boot, it hasbeen found that there is a tendency for air to leak from the outsideinto the boot to lower the amount of vacuum (i.e., increase thepressure) within the boot. The invention herein prevents loss of vacuumso that the system is more effective and efficient.

It is therefore an object of this invention to provide a boot or shoewhich will not have the drawbacks of prior art footwear. Primarily, itis an object of this invention to provide a system to conform a boot tothe users foot to fit the users foot evenly and tightly over all partsof the foot. Also, an objective of the invention is to provide a bootthat will not melt or soften at temperatures likely to be reached innormal use. A further object is to correct the shaft of the boot, theangle which the leg makes with the foot. A further object of theinvention is to provide a system whereby the foot is protected from hotmaterial to thereby ease discomfort.

BRIEF DESCRIPTION OF THE INVENTION These objects are accomplished byhaving a system for providing support for the foot which includes bootmeans formed with a shell of moldable material. An essentially air tightbag means is placed around the shell to seal the boot means. Thereafter,vacuum means acting inside the bag means cause the bag to create a lowerthan ambient pressure within the bag means to exert a force on theshell. Heating means cause the shell means to reach a moldabletemperature whereby the vacuum acts on the shell when the shell is atthe moldable temperature tocause the boot to form to the foot. Thencooling means are applied to the boot while the vacuum is beingmaintained until the boot drops below the molding temperature. The usersfoot may be withdrawn from the boot and a boot of perfect fit isobtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a side view of the bootinserted within a plastic bag.

FIG. 2 shows the bag being sealed around the users leg with the bootwithin the bag.

FIG. 3 shows the sealed bag with the vacuum having veen applied so thatthe bag is compressed around the boot.

FIG. 4 is a sectional view through section IVIV of FIG. 3 of the boot.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Boot means are formedwith a shell of moldable material. In the preferred embodiment, suchboot means 10 is formed of a shell 17 formed of a thermoplastic materialwhich is rigid at room temperature and becomes moldable with memorybetween l80F and 380F, preferably about 350F. At that temperature, acompromise is reached between the highest temperatures to which the footcan be subjected and temperatures to which the boot might ordinarily besubjected in a heated automobile trunk or near a fireplace or wallheater. The shell is lined with neoprene rubber at 16 also of aconsistent thickness for insulation from heat and cold and for evenlycushioning the foot from the hard plastic material. The boot alsocomprises a sole 11 made to conform to a ski binding, an ankle portion12, and an instep portion 13. Additionally, a buckle 14 allows theinstep portion 13 to be moved to allow insertion and removal of thefoot.

Essentially, the major difference between the Kahmann application andthe invention herein, is the use of air tight sealing means forplacement around the shell which seals the boot means. In the exemplaryembodiment, such sealing means 20 comprises a bag made of a film ofpolyethylene terephthalete, such as sold under the trademark Mylar, orof other plastic materi als, metallic material, rubber, or anycombination of these materials. The chosen material should be flexibleso that it will conform to the boot, beinga thin film so that it willnot insulate the boot from applied heating and cooling, and must have amelting point higher than the molding temperature than that of the shellof the boot. Mylar is the preferable material because it has a sharpmelting point above 400F, or about 50F higher than the boots softeningpoint. Mylar bags are available and because they are transparent, theboot may be inspected visually while it is within the bag. After theboot is placed on the foot, the boot is placed within the bag and thebag is sealed by appropriate means. In the preferred embodiment, suchmeans includes an elastic band 23 placed around the top of the bag 22and around the users leg 1. The elastic band 23 is made tight enough sothat no air can pass between the top of the bag 22 and the leg 1.

Vacuum means lowers the pressure within the sealing means below ambientpressure so that atmosphere pressure exerts a resultin g force on theoutside of the sealing means to apply external pressure to the shell. Inthe exemplary embodiment such vacuum means 50 includes a tube 51connected to a source of vacuum (not shown) nearby. The vacuum line 51is placed within the bag adjacent the boot shell preferably near thebuckle. In the position shown in FIG. 1, a pad of soft material 15 isplaced over the buckle near the end of the tubing. This flexing materialserves to protect the bag 21 from the sharp buckle 14.

Referring now to FIG. 2, the elastic band 23 has been placed around theleg to make an air tight seal around the boot.

In FIG. 3, the vacuum means 50 has applied a vacuum through the vacuumtube 51 to draw the bag tightly around the shell of the boot. Heatingmeans heats the shell means to a moldable temperature whereby the vacuumacts on the shell to cause the boot to conform to the foot. In theexemplary embodiment, such heating means comprises a heater source 30.The heater source could be many different heating means. We have foundthat an industrial hand-held blower with an electrical resistanceheating element is a preferred source of heat. These heating blowers arecapable of directing hot air at a specific location by holding theoutput end of the blower near that location, or they can heat a generalarea by holding the outputend farther away from the material to beheated. This feature allows flexibility in the use of this invention.Such heating blowers are capable of temperatures high enough to heat theshell to its softening point, about 350F. It is also possible with thistype of blower to direct the heat away from the uncovered portion of theusers leg.

Another heat source which may be used is a miniature electric blanket.Preferably, the heating elements are within a heat resistant andelectrically insulated material. The blanket has the same area as thearea of the largest boot sold, and is designed and shaped to fit on aboot with minimum folding. Alternatively, more than one blanket, each ofa particular shape to heat a particular section of the boot could beused.

The blanket has certain advantages. For example, heat is more evenlyapplied to the boot and there is less use of energy than with a blower.The blanket system also might be quieter than a blower which may beimportant to a retail store where excess noise might irritate customers.If multiple blankets are used, heating of particular sections may beaccomplished if desired. Other known heat sources could also be used butit is advantageous that they be portable and may be applied withoutmoving the boot.

As the shell reaches its softening point, the atmospheric pressure willexert forces on the shell to cause it to move inwardly to conform to theusers foot. If the boot is too tight when bought, the force exerted bythe users foot against the boot will cause it to expand slightly toevenly conform to his foot. It has been possible to develop very highvacuum within such an arrangement and the atmospheric pressure can actvery quickly on the shell. Therefore, it is unnecessary to maintain theboot at an elevated temperature for a long period of time. There is nodiscomfort to the wearer because his foot is protected by the neopreneliner 16 and optionally by a sock 2.

While the pressure is maintained on the shell, the shell cools below itsmolding temperature. This cooling may be accelerated by applying acooling means to the boot while the vacuum is maintained at least untilthe temperature of the boot drops below the softening temperature. Inthe exemplary embodiment, such cooling means includes a cooling source40. Preferably, this cooling source is an aerosol coolant which can besprayed directly on the outside of the bag. This method will cool theboot very rapidly. Of course, a water bath could also be used but it isdesirable that the foot not be moved during the process sothat the bootwill conform to the users foot when it is in its supporting position. Itis advisable to maintain the vacuum at least until the boot drops belowthe molding temperature so that forces exerted by the foot outsideagainst the inside of the shell will .not cause any non-conformingregions within the boot.

Shaft of a ski boot is defined as the angle which the ankle portion ofthe boot 12 makes with the rest of the boot. It should conform to theangle which the leg makes to the foot. The concept of shaft can beillustrated by picturing a set of regular leather boots which have beenworn for some time. If they are placed on a flat surface, a slight bendshould be evident about the ankle, and the boot should naturallymaintain this angle or shaft. The present device assures a correct shaftbecause the user should be standing naturally on a flat surface and asheat is applied to the top portion of the boot, it will bend slightly toassume the correct shaft.

It should also be noted that by allowing outside air to bethe source ofpressure to the shell, the heating and cooling means can be applied tothe boot while the boot is undergoing pressure deformation. This isimportant because the boot would have to be heated to a higher initialtemperature so that the pressure applying means could be placed aroundthe boot as the boot cooled to its minimum molding temperature. Also,the pressure applying means would have to be removed from the boot ifcooling means were applied to the boot and without such pressure, theboot could deform during cooling. Without the use of cooling means sothat the pressure could be maintained, the warm boot would stay on theusers foot a longer period of time, and if the pressure means is stillaround the boot, it inhibits ambient air from reaching the boot to coolthe shell.

Because the boot may be heated and cooled quickly, boots of a materialof higher softening temperature may be used. This guards againstaccidental deformation of the boot from the heat of a fireplace or in anautomobile trunk. Also, the neoprene lining protects the foot during theshort heating period.

If for any reason the shape of the users foot changed, the process couldbe repeated quickly. If the user decided to sell his boots, his customformed boots could be modified to become the buyers custom. boots iftheir feet are of similar size.

Thus, we have shown an improved system for conforming a shoe or boot toa foot including boot means 10 of a material which is moldable at acertain temperature. Heating means 30 heats the boot to the temperature.Pressure applying means molds the boot to the foot. The improvementincludes the provision of having a vacuum means applying a vacuum fromwithin the boot to cause the boot to collapse around the foot. In orderto improve the vacuum application, a sealing means 20 in the form of anair tight bag 21 sealed tightly around the users leg is placed aroundthe boot and a vacuum tube 51 placed therewithin to evacuate air withinthe bag so that atmospheric pressure exerts resulting forces on theoutside of the sealing means to apply external pressure on the shell.

I claim:

1. A method of forming a boot or shoe of moldable material to betterconform it to a users foot after hav ing placed the boot on the usersfoot including the steps of:

a. surrounding the boot with a flexible, air tight material with amelting temperature higher than that of the molding temperature of theboot;

b. making an air tight seal between the flexible, air

tight material and the boot;

c. applying a vacuum beneath said flexible air tight materials;

d. applying sufficient heat to the boot for the boot material to becomemoldable while maintaining the vacuum so that the vacuum will cause theboot to mold toward the foot to conform thereto.

2. The method of claim 1 further including the step of applying coolingmeans to the boot at least until the boot material drops below themolding temperature while maintaining the vacuum.

3. In a system for providing better support for a foot;

boot means formed of a shell of moldable material;

essentially air tight sealing means for placement around said shell toseal the boot means;

vacuum means for acting inside said sealing means for lowering thepressure within said sealing means below ambient pressure so thatatmospheric pressure exerts a resulting force on the outside of thesealing means to apply external pressure to the shell; heating means forheating said shell to a moldable temperature whereby the vacuum acts onsaid shell when said shell is at a moldable temperature to cause saidboot to conform to the foot.

4. The system of claim 3 further including cooling means for coolingsaid boot at least below the molding temperature while the vacuum ismaintained at least until the boot drops below the molding temperature.

5. In an improved system for conforming a shoe or boot to a footincluding: I

boot means of material which is moldable at a certain temperature;heating means to heat said boot to said temperature;

and pressure applying means to mold the boot to the foot, theimprovement including the provision of having;

a. said pressure means includes means to apply a vacuum from within saidboot to cause said boot to collapse around the foot b. sealing meansplaceable around said boot to seal said boot from the atmosphere wherebysaid vacuum acts within said sealing means to provide a 6. The improvedsystem of claim 5, further including lowered pressure within saidsealing means so the provision of having cooling means acting on thethat atmospheric pressure exerts resulting forces boot while the vacuumis maintained to cool the boot on the outside of the sealing means toapply exbelow the molding temperature. ternal pressure to the boot.

1. A method of forming a boot or shoe of moldable material to betterconform it to a user''s foot after having placed the boot on the user''sfoot including the steps of: a. surrounding the boot with a flexible,air tight material with a melting temperature higher than that of themolding temperature of the boot; b. making an air tight seal between theflexible, air tight material and the boot; c. applying a vacuum beneathsaid flexible air tight materials; d. applying sufficient heat to theboot for the boot material to become moldable while maintaining thevacuum so that the vacuum will cause the booT to mold toward the foot toconform thereto.
 2. The method of claim 1 further including the step ofapplying cooling means to the boot at least until the boot materialdrops below the molding temperature while maintaining the vacuum.
 3. Ina system for providing better support for a foot; boot means formed of ashell of moldable material; essentially air tight sealing means forplacement around said shell to seal the boot means; vacuum means foracting inside said sealing means for lowering the pressure within saidsealing means below ambient pressure so that atmospheric pressure exertsa resulting force on the outside of the sealing means to apply externalpressure to the shell; heating means for heating said shell to amoldable temperature whereby the vacuum acts on said shell when saidshell is at a moldable temperature to cause said boot to conform to thefoot.
 4. The system of claim 3 further including cooling means forcooling said boot at least below the molding temperature while thevacuum is maintained at least until the boot drops below the moldingtemperature.
 5. In an improved system for conforming a shoe or boot to afoot including: boot means of material which is moldable at a certaintemperature; heating means to heat said boot to said temperature; andpressure applying means to mold the boot to the foot, the improvementincluding the provision of having; a. said pressure means includes meansto apply a vacuum from within said boot to cause said boot to collapsearound the foot b. sealing means placeable around said boot to seal saidboot from the atmosphere whereby said vacuum acts within said sealingmeans to provide a lowered pressure within said sealing means so thatatmospheric pressure exerts resulting forces on the outside of thesealing means to apply external pressure to the boot.
 6. The improvedsystem of claim 5, further including the provision of having coolingmeans acting on the boot while the vacuum is maintained to cool the bootbelow the molding temperature.